That’s in contrast to physician Annette Bosworth, whose last fundraising report revealed an impressive $315,000 haul, the best of the rest of the GOP primary field in South Dakota, but also more debt than she had cash on hand.

Rounds is the front-runner in the primary, and if he wins the nomination, he’ll take on Democrat Rick Weiland in the general election. Republicans are favored to pick up South Dakota's open seat following Sen. Tim Johnson's (D) retirement.